Given the task definition and input, reply with output. In this task, you are given a context and four options. Each option is a suggested ending for the context. You should read the context and pick the best ending for the context. Please answer with "A", "B", "C", and "D". 

[header] How to tell the difference between twins [title] Observe their facial features. [step] Twins often have different shaped eyes, jawlines, cheekbones, lips and other facial features, including moles or birthmarks on the opposite sides of their bodies that can help you tell them apart. You might also notice that one has a darker skin tone or complexion. <sep> (A) [title] Look closely at how their height differs. [step] You may discover that one twin is taller than the other, or tends to stand up a little straighter than his or her sibling. (B) [substeps] Twins may think that their noses are slightly too large or that they have more lips. They may also not have their noses closer than your own nose when in doubt. (C) Because twins are so closely related, the similarities often display between twins come from historical or cultural backgrounds. [substeps] Boys and girls typically have slightly different skin tones. (D) This can be a sign that your twins have different facial characteristics than you! It's best to get a blood test done so you can be certain. [substeps] Twins have fangs both above the lip and below their teeth.

A